Description:
<jats:p>Although known previously from only two specimens from northern Greenland, new material from Marjuman boulders in debris flows of the Cow Head Group of western Newfoundland demonstrate that <jats:italic>Verditerrina</jats:italic> Robison is a menomoniid trilobite that is closely related to <jats:italic>Hysteropleura</jats:italic> Raymond. Following a parsimony analysis using the PAUP program, <jats:italic>Verditerrina</jats:italic> is used at the subgeneric level to label a distinctive monophyletic group within <jats:italic>Hysteropleura.</jats:italic> Three new species are established for the Newfoundland material: <jats:italic>Hysteropleura</jats:italic> (<jats:italic>Verditerrina</jats:italic>) <jats:italic>adraini, H.</jats:italic> (<jats:italic>V.</jats:italic>) <jats:italic>edgecombei</jats:italic> and <jats:italic>H.</jats:italic> (<jats:italic>V.</jats:italic>) <jats:italic>ramskoldi.</jats:italic> All three species undergo substantial modification of the anterior border of the cranidium during holaspid ontogeny. Two of the species, <jats:italic>H.</jats:italic> (<jats:italic>V.</jats:italic>) <jats:italic>adraini</jats:italic> and <jats:italic>H.</jats:italic> (<jats:italic>V.</jats:italic>) <jats:italic>edgecombei</jats:italic>, develop elongate, tongue-like borders that are reminiscent of those of calymenids such as <jats:italic>Spathocalymene</jats:italic> Tillman.</jats:p>